Marangoni effect

About: Marangoni effect is a research topic. Over the lifetime, 5336 publications have been published within this topic receiving 98562 citations. The topic is also known as: Gibbs–Marangoni effect.

Marangoni and Buoyancy Effects on Direct Metal Laser Sintering with a Moving Laser Beam

Abstract: A three-dimensional model describing melting and resolidification of a direct metal laser sintering process under the irradiation of a moving Gaussian laser beam is developed. Effects of shrinkage and natural convection driven by the surface tension and buoyancy force are taken into account. The energy equation is formulated using a temperature-transforming model and solved by the finite-volume method. The temperature distribution and velocity field are investigated. The results show that increasing the initial porosity of the powder bed enlarges the depth of the melt–solid interface and that the laser intensity has great influence on both the depth and width of the liquid pool. The whole molten pool shifts toward the direction opposite the laser scanning as the scanning velocity increases.

Steady Marangoni flow traveling with chemical fronts.

Abstract: When autocatalytic chemical fronts propagate in thin layers of solution in contact with air, they can induce capillary flows due to surface tension gradients across the front (Marangoni flows). We investigate here such an interplay between autocatalytic reactions, diffusion, and Marangoni effects with a theoretical model coupling the incompressible Navier-Stokes equations to a conservation equation for the autocatalytic product concentration in the absence of gravity and for isothermal conditions. The boundary condition at the open liquid/air interface takes the surface activity of this product into account and introduces the solutal Marangoni number M representing the intensity of the coupling between hydrodynamics and reaction-diffusion processes. Positive and negative Marangoni numbers correspond, respectively, to the cases where the product decreases or increases surface tension behind the front. We show that, in both cases, such coupled systems reach an asymptotic dynamics characterized by a steady fluid vortex traveling at a constant speed with the front and deforming it, with, however, an asymmetry between the results for positive and negative M. A parametric study shows that increased propagation speed, front deformation, and possible transient oscillating dynamics occur when the absolute value of M is increased.

Effect of surfactant on the long-wave instability of a shear-imposed liquid flow down an inclined plane

Abstract: The effect of an insoluble surfactant on the linear stability of a shear-imposed flow down an inclined plane is examined in the long-wavelength limit. It has been known that a free falling film flow with surfactant is stable to long-wavelength disturbances at sufficiently small Reynolds numbers. Imposing an additional interfacial shear, however, could cause instability due to the shear-induced Marangoni effect. Two modes of the stability are identified and the corresponding growth rates are derived. The underlying mechanisms of the stability are also elucidated in detail.

Dispensing Surfactants from Electrodes: Marangoni Phenomenon at the Surface of Aqueous Solutions of (11-Ferrocenylundecyl)trimethylammonium Bromide

Abstract: Electrochemical methods in combination with redox-active surfactants form the basis of a procedure to create gradients in surfactant-based properties of solutions. The gradients are created by the ...

Modelling of marangoni effects in electron beam melting

Abstract: Electron beam melting processes exhibit large thermal gradients in the region where the electron beam intercepts the melt; this leads to variations in the surface energy of the melt close to the be...